Trans-Cricothyroid Membrane Injection of Local Anesthesia Attenuates Cough Response and Postoperative Sore Throat to the Nasotracheal Tube

Objective: This study aims to investigate the effects of trans-cricothyroid membrane injection of local anesthesia on cough response and postoperative sore throat to the nasotracheal tube.

Methods: Patients who require general anesthesia with nasotracheal tube for oral and maxillofacial surgery were randomised divided into groups L and C. The patients in group L received trans-cricothyroid membrane injection of 2% lidocaine (3 mL) before anesthesia. Meanwhile, the same volume of 0.9% saline was administered to group C. The incidences of cough response, mean arterial pressure (MAP) and heart rate (HR) were recorded during emergency from general anesthesia. Postoperative sore throat (POST) was assessed at 1, 6, 12 and 24 h after surgery.

Results: The data of 60 patients in group L and 61 in group C were included in this study. The incidence of cough was lower in group L than in group C, ie, 41.7% vs 67.2% upon extubation (=0.006) and 20.0% vs 41.0% at five minutes after extubation (=0.018). MAP and HR in group L were significantly lower than in group C during emergency from general anesthesia (<0.05). POST incidence was significantly reduced in group L at 1 and 6 h after surgery, ie, 35.0% vs 55.7% at 1 h after surgery (=0.029) and 20.0% vs 37.7% at 6 h after surgery (=0.044).

Conclusion: Trans-cricothyroid membrane injection of local anesthesia is a simple and effective method to attenuate the incidence of cough response during emergency from general anesthesia. This technique can reduce the incidence of POST after surgery.